What indicates a left turn lane at an intersection?

A dedicated lane marked with a left-turn arrow is a clear indicator of a left turn lane at an intersection. This specific marking directs drivers that they should position their vehicles in this lane when intending to turn left. The left-turn arrow helps prevent confusion about lane usage and enhances traffic safety by signaling the correct movement to both the drivers using the lane and those in adjacent lanes.

While a sign displaying 'left turn only' can also indicate that the lane is for left turns, it is not as visually immediate or clear as the left turn arrow painted directly on the road. A traffic signal directing left turns may govern when a driver can make that turn, but it does not mark the physical lane itself. Similarly, a solid white line can delineate lanes, but it does not specifically indicate that lane usage is for left turns. The left-turn arrow is the most unambiguous and universally recognized signal for this purpose.